Taittirīyopaniṣat 03.06

स तपोऽतप्यत। स तपस्तप्त्वा। आनन्दो ब्रह्मेति व्यजानात्। आनन्दाद्ध्येव खल्विमानि भूतानि जायन्ते। आनन्देेन जातानि जीवन्ति। आनन्दं प्रयन्त्यभिसंविशन्तीति ॥६॥

sa tapo-'tapyata। sa tapas-taptvā। ānando brahmeti vyajānāt। ānandāddhyeva khalvimāni bhūtāni jāyante। ānandena jātāni jīvanti। ānandaṃ prayanty-abhisaṃviśantīti ॥6॥

[स (sa) - he; तपः (tapaḥ) - austerity; अतप्यत (atapyata) - practiced; स (sa) - he; तपः (tapaḥ) - austerity; तप्त्वा (taptvā) - having practiced; आनन्दः (ānandaḥ) - bliss; ब्रह्म (brahma) - Brahman; इति (iti) - thus; व्यजानात् (vyajānāt) - realized; आनन्दात् (ānandāt) - from bliss; हि (hi) - indeed; एव (eva) - only; खलु (khalu) - verily; इमानि (imāni) - these; भूतानि (bhūtāni) - beings; जायन्ते (jāyante) - are born; आनन्देन (ānandena) - by bliss; जातानि (jātāni) - having been born; जीवन्ति (jīvanti) - live; आनन्दम् (ānandam) - bliss; प्रयन्ति (prayanti) - depart; अभिसंविशन्ति (abhisaṃviśanti) - merge; इति (iti) - thus;]

He performed austerity. After practicing austerity, he realized that "Bliss is Brahman." Indeed, from bliss alone are all these beings born; by bliss they live after being born, and into bliss they depart and merge.